sys/sys/linker.h

   1 /*-
   2  * Copyright (c) 1997 Doug Rabson
   3  * All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  *
  14  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  15  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  16  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  17  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  18  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  19  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  20  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  21  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  22  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  23  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  24  * SUCH DAMAGE.
  25  *
  26  * $FreeBSD: src/sys/sys/linker.h,v 1.17.2.1 2002/03/11 01:13:53 dd Exp $
  27  */
  28
  29 #ifndef _SYS_LINKER_H_
  30 #define _SYS_LINKER_H_
  31
  32 #ifndef _SYS_TYPES_H_
  33 #include <sys/types.h>
  34 #endif
  35 #ifndef _SYS_PARAM_H_
  36 #include <sys/param.h>
  37 #endif
  38
  39 #ifdef _KERNEL
  40
  41 #ifndef _SYS_QUEUE_H_
  42 #include <sys/queue.h>
  43 #endif
  44 #include <machine/elf.h>
  45
  46 #include <sys/module.h>
  47
  48 #ifdef MALLOC_DECLARE
  49 MALLOC_DECLARE(M_LINKER);
  50 #endif
  51
  52 /*
  53  * Object representing a file which has been loaded by the linker.
  54  */
  55 typedef struct linker_file* linker_file_t;
  56 typedef TAILQ_HEAD(, linker_file) linker_file_list_t;
  57
  58 typedef caddr_t linker_sym_t;           /* opaque symbol */
  59 typedef c_caddr_t c_linker_sym_t;       /* const opaque symbol */
  60
  61 /*
  62  * expanded out linker_sym_t
  63  */
  64 typedef struct linker_symval {
  65     const char*         name;
  66     caddr_t             value;
  67     size_t              size;
  68 } linker_symval_t;
  69
  70 struct linker_file_ops {
  71     /*
  72      * Lookup a symbol in the file's symbol table.  If the symbol is
  73      * not found then return ENOENT, otherwise zero.  If the symbol
  74      * found is a common symbol, return with *address set to zero and
  75      * *size set to the size of the common space required.  Otherwise
  76      * set *address the value of the symbol.
  77      */
  78     int                 (*lookup_symbol)(linker_file_t, const char* name,
  79                                          c_linker_sym_t* sym);
  80
  81     int                 (*symbol_values)(linker_file_t, c_linker_sym_t,
  82                                          linker_symval_t*);
  83
  84     int                 (*search_symbol)(linker_file_t, caddr_t value,
  85                                          c_linker_sym_t* sym, long* diffp);
  86
  87     /*
  88      * Completes the loading task started in preload_file.
  89      */
  90     int                 (*preload_finish)(linker_file_t);
  91
  92     /*
  93      * Unload a file, releasing dependancies and freeing storage.
  94      */
  95     void                (*unload)(linker_file_t);
  96
  97     int                 (*lookup_set)(linker_file_t, const char *name,
  98                                         void ***firstp, void ***lastp, int *countp);
  99 };
 100
 101 struct common_symbol {
 102     STAILQ_ENTRY(common_symbol) link;
 103     char*               name;
 104     caddr_t             address;
 105 };
 106
 107 struct linker_file {
 108     int                 refs;           /* reference count */
 109     int                 userrefs;       /* kldload(2) count */
 110     int                 flags;
 111 #define LINKER_FILE_LINKED      0x1     /* file has been fully linked */
 112     TAILQ_ENTRY(linker_file) link;      /* list of all loaded files */
 113     char*               filename;       /* file which was loaded */
 114     int                 id;             /* unique id */
 115     caddr_t             address;        /* load address */
 116     size_t              size;           /* size of file */
 117     int                 ndeps;          /* number of dependancies */
 118     linker_file_t*      deps;           /* list of dependancies */
 119     STAILQ_HEAD(, common_symbol) common; /* list of common symbols */
 120     TAILQ_HEAD(, module) modules;       /* modules in this file */
 121     TAILQ_ENTRY(linker_file) loaded;    /* preload dependency support */
 122     void*               priv;           /* implementation data */
 123
 124     struct linker_file_ops* ops;
 125 };
 126
 127 /*
 128  * Object implementing a class of file (a.out, elf, etc.)
 129  */
 130 typedef struct linker_class *linker_class_t;
 131 typedef TAILQ_HEAD(, linker_class) linker_class_list_t;
 132
 133 struct linker_class_ops {
 134     /*
 135      * Load a file, returning the new linker_file_t in *result.  If
 136      * the class does not recognise the file type, zero should be
 137      * returned, without modifying *result.  If the file is
 138      * recognised, the file should be loaded, *result set to the new
 139      * file and zero returned.  If some other error is detected an
 140      * appropriate errno should be returned.
 141      */
 142     int         (*load_file)(const char *filename, linker_file_t *result);
 143     /*
 144      * Same as load_file, but does not load dependencies.  Necessary
 145      * for tentatively loading (loader-)preloaded modules.
 146      */
 147     int         (*preload_file)(const char *filename, linker_file_t *result);
 148 };
 149
 150 struct linker_class {
 151     TAILQ_ENTRY(linker_class) link;     /* list of all file classes */
 152     const char*         desc;           /* description (e.g. "a.out") */
 153     void*               priv;           /* implementation data */
 154
 155     struct linker_class_ops *ops;
 156 };
 157
 158 /*
 159  * Function type used when iterating over the list of linker files.
 160  */
 161 typedef int linker_predicate_t(linker_file_t, void *);
 162
 163 /*
 164  * The file which is currently loading.  Used to register modules with
 165  * the files which contain them.
 166  */
 167 extern linker_file_t    linker_current_file;
 168
 169 /*
 170  * The "file" for the kernel.
 171  */
 172 extern linker_file_t    linker_kernel_file;
 173
 174 /*
 175  * Add a new file class to the linker.
 176  */
 177 int linker_add_class(const char* _desc, void* _priv,
 178                      struct linker_class_ops* _ops);
 179
 180 /*
 181  * Load a file, trying each file class until one succeeds.
 182  */
 183 int linker_load_file(const char *_filename, linker_file_t *_result);
 184
 185 /*
 186  * Find a currently loaded file given its filename.
 187  */
 188 linker_file_t linker_find_file_by_name(const char* _filename);
 189
 190 /*
 191  * Find a currently loaded file given its file id.
 192  */
 193 linker_file_t linker_find_file_by_id(int _fileid);
 194
 195 /*
 196  * Called from a class handler when a file is laoded.
 197  */
 198 linker_file_t linker_make_file(const char* _filename, void* _priv,
 199                                struct linker_file_ops* _ops);
 200
 201 /*
 202  * Unload a file, freeing up memory.
 203  */
 204 int linker_file_unload(linker_file_t _file);
 205
 206 /*
 207  * Add a dependancy to a file.
 208  */
 209 void linker_file_add_dependancy(linker_file_t _file, linker_file_t _dep);
 210
 211 int linker_load_dependencies(linker_file_t lf);
 212
 213 /*
 214  * Iterate over all of the currently loaded linker files calling the
 215  * predicate function while the function returns 0.  Returns the value
 216  * returned by the last predicate function.
 217  */
 218 int linker_file_foreach(linker_predicate_t *_predicate, void *_context);
 219
 220 /*
 221  * Lookup a symbol in a file.  If deps is TRUE, look in dependancies
 222  * if not found in file.  The symbol's value is returned in the
 223  * caddr_t.  An error is returned, 0 if no error occured.
 224  */
 225 int linker_file_lookup_symbol(linker_file_t _file, const char* _name,
 226                             int _deps, caddr_t *);
 227
 228
 229 /*
 230  * Lookup a linker set in a file.  Return pointers to the first entry,
 231  * last + 1, and count of entries.  Use: for (p = start; p < stop; p++) {}
 232  * void *start is really: "struct yoursetmember ***start;"
 233  */
 234 int linker_file_lookup_set(linker_file_t _file, const char *_name,
 235                             void *_start, void *_stop, int *_count);
 236
 237 /*
 238  * Search the linker path for the module.  Return the full pathname in
 239  * a malloc'ed buffer.
 240  */
 241 char *linker_search_path(const char *_filename);
 242
 243 int linker_reference_module(const char *modname, struct mod_depend *verinfo,
 244     linker_file_t *retult);
 245 int linker_release_module(const char *modname, struct mod_depend *verinfo,
 246     linker_file_t lf);
 247
 248 /*
 249  * DDB Helpers, tuned specifically for ddb/db_kld.c
 250  */
 251 int linker_ddb_lookup(const char *_symstr, c_linker_sym_t *_sym);
 252 int linker_ddb_search_symbol(caddr_t _value, c_linker_sym_t *_sym,
 253                              long *_diffp);
 254 int linker_ddb_symbol_values(c_linker_sym_t _sym, linker_symval_t *_symval);
 255
 256
 257 #endif  /* _KERNEL */
 258
 259 /*
 260  * Module information subtypes
 261  */
 262 #define MODINFO_END             0x0000          /* End of list */
 263 #define MODINFO_NAME            0x0001          /* Name of module (string) */
 264 #define MODINFO_TYPE            0x0002          /* Type of module (string) */
 265 #define MODINFO_ADDR            0x0003          /* Loaded address */
 266 #define MODINFO_SIZE            0x0004          /* Size of module */
 267 #define MODINFO_EMPTY           0x0005          /* Has been deleted */
 268 #define MODINFO_ARGS            0x0006          /* Parameters string */
 269 #define MODINFO_METADATA        0x8000          /* Module-specfic */
 270
 271 #define MODINFOMD_AOUTEXEC      0x0001          /* a.out exec header */
 272 #define MODINFOMD_ELFHDR        0x0002          /* ELF header */
 273 #define MODINFOMD_SSYM          0x0003          /* start of symbols */
 274 #define MODINFOMD_ESYM          0x0004          /* end of symbols */
 275 #define MODINFOMD_DYNAMIC       0x0005          /* _DYNAMIC pointer */
 276 #define MODINFOMD_ENVP          0x0006          /* (from 5.x) envp[] */
 277 #define MODINFOMD_HOWTO         0x0007          /* (from 5.x) boothowto */
 278 #define MODINFOMD_KERNEND       0x0008          /* (from 5.x) kernend */
 279 #define MODINFOMD_SHDR          0x0009          /* section header table */
 280 #define MODINFOMD_FW_HANDLE     0x000a          /* Firmware dependent handle */
 281 #define MODINFOMD_NOCOPY        0x8000          /* don't copy this metadata to the kernel */
 282
 283 #define MODINFOMD_DEPLIST       (0x4001 | MODINFOMD_NOCOPY)     /* depends on */
 284
 285 #ifdef _KERNEL
 286 #define MD_FETCH(mdp, info, type) ({ \
 287         type *__p; \
 288         __p = (type *)preload_search_info((mdp), MODINFO_METADATA | (info)); \
 289         __p ? *__p : 0; \
 290 })
 291 #endif
 292
 293 #define LINKER_HINTS_VERSION    1               /* linker.hints file version */
 294
 295 #ifdef _KERNEL
 296
 297 /*
 298  * Module lookup
 299  */
 300 extern caddr_t          preload_metadata;
 301 extern caddr_t          preload_search_by_name(const char *);
 302 extern caddr_t          preload_search_by_type(const char *);
 303 extern caddr_t          preload_search_next_name(caddr_t);
 304 extern caddr_t          preload_search_info(caddr_t, int);
 305 extern void             preload_delete_name(const char *);
 306 extern void             preload_bootstrap_relocate(vm_offset_t);
 307 extern struct mod_metadata *find_mod_metadata(const char *);
 308
 309 #ifdef KLD_DEBUG
 310
 311 extern int kld_debug;
 312 #define KLD_DEBUG_FILE  1       /* file load/unload */
 313 #define KLD_DEBUG_SYM   2       /* symbol lookup */
 314
 315 #define KLD_DPF(cat, args)                                      \
 316         do {                                                    \
 317                 if (kld_debug & KLD_DEBUG_##cat) kprintf args;  \
 318         } while (0)
 319
 320 #else
 321
 322 #define KLD_DPF(cat, args)
 323
 324 #endif
 325
 326 typedef int elf_lookup_fn(linker_file_t, Elf_Size, int, Elf_Addr *);
 327
 328 /* Support functions */
 329 int     elf_reloc(linker_file_t, Elf_Addr, const void *, int, elf_lookup_fn);
 330 int     elf_reloc_local(linker_file_t, Elf_Addr, const void *, int, elf_lookup_fn);
 331 Elf_Addr elf_relocaddr(linker_file_t, Elf_Addr);
 332
 333 /* values for type */
 334 #define ELF_RELOC_REL   1
 335 #define ELF_RELOC_RELA  2
 336
 337 #endif /* _KERNEL */
 338
 339 struct kld_file_stat {
 340     int         version;        /* set to sizeof(linker_file_stat) */
 341     char        name[MAXPATHLEN];
 342     int         refs;
 343     int         id;
 344     caddr_t     address;        /* load address */
 345     size_t      size;           /* size in bytes */
 346 };
 347
 348 struct kld_sym_lookup {
 349     int         version;        /* set to sizeof(struct kld_sym_lookup) */
 350     const char  *symname;       /* Symbol name we are looking up */
 351     u_long      symvalue;
 352     size_t      symsize;
 353 };
 354
 355 #define KLDSYM_LOOKUP   1
 356
 357 #ifndef _KERNEL
 358
 359 #ifndef _SYS_CDEFS_H_
 360 #include <sys/cdefs.h>
 361 #endif
 362
 363 __BEGIN_DECLS
 364 int     kldload(const char *);
 365 int     kldunload(int);
 366 int     kldfind(const char *);
 367 int     kldnext(int);
 368 int     kldstat(int, struct kld_file_stat *);
 369 int     kldfirstmod(int);
 370 int     kldsym(int, int, void *);
 371 __END_DECLS
 372
 373 #endif
 374
 375 #endif /* !_SYS_LINKER_H_ */